David McCreedy added CURLOPT_SOCKOPTFUNCTION and CURLOPT_SOCKOPTDATA to

allow applications to set their own socket options.

lib/connect.c

@@ -702,6 +702,17 @@ singleipconnect(struct connectdata *conn,
 
   nosigpipe(conn, sockfd);
 
+  if(data->set.fsockopt) {
+    /* activate callback for setting socket options */
+    error = data->set.fsockopt(data->set.sockopt_client,
+                               sockfd,
+                               CURLSOCKTYPE_IPCXN);
+    if (error) {
+      sclose(sockfd); /* close the socket and bail out */
+      return CURL_SOCKET_BAD;
+    }
+  }
+
   /* possibly bind the local end to an IP, interface or port */
   res = bindlocal(conn, sockfd);
   if(res) {

lib/setup.h

@@ -278,19 +278,6 @@ int fileno( FILE *stream);
 
 #endif /* WIN32 */
 
-#ifndef curl_socket_typedef
-/* now typedef our socket type */
-#ifdef WIN32
-typedef SOCKET curl_socket_t;
-#define CURL_SOCKET_BAD INVALID_SOCKET
-#else
-typedef int curl_socket_t;
-#define CURL_SOCKET_BAD -1
-#endif
-#define curl_socket_typedef
-#endif /* curl_socket_typedef */
-
-
 #if defined(WIN32) && !defined(__CYGWIN__) && !defined(USE_ARES) && \
     !defined(__LCC__)  /* lcc-win32 doesn't have _beginthreadex() */
 #ifdef ENABLE_IPV6

lib/url.c

@@ -1551,6 +1551,20 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option,
     data->set.ftp_alternative_to_user = va_arg(param, char *);
     break;
 
+  case CURLOPT_SOCKOPTFUNCTION:
+    /*
+     * socket callback function: called after socket() but before connect()
+     */
+    data->set.fsockopt = va_arg(param, curl_sockopt_callback);
+    break;
+
+  case CURLOPT_SOCKOPTDATA:
+    /*
+     * socket callback data pointer. Might be NULL.
+     */
+    data->set.sockopt_client = va_arg(param, void *);
+    break;
+
   default:
     /* unknown tag and its companion, just ignore: */
     result = CURLE_FAILED_INIT; /* correct this */

lib/urldata.h

@@ -1029,6 +1029,8 @@ struct UserDefined {
   curl_progress_callback fprogress;  /* function for progress information */
   curl_debug_callback fdebug;      /* function that write informational data */
   curl_ioctl_callback ioctl;       /* function for I/O control */
+  curl_sockopt_callback fsockopt;  /* function for setting socket options */
+  void *sockopt_client; /* pointer to pass to the socket options callback */
 
   /* the 3 curl_conv_callback functions below are used on non-ASCII hosts */
   /* function to convert from the network encoding: */